Blind rivet pulling tool

ABSTRACT

An improved fluid operated rivet pulling tool for forming a head on the far side of the work. The tool is adaptable to use on a variety of rivet sizes with minor addition or interchange of parts such as an additional piston and associated cylinder block with ports.

United States Patent 11 1 1 1 3,714,810 Boyd 1451 Feb. 6, 1973 BLIND RIVET PULLING TOOL [75] Inventor: Clive Reginald Boyd, Artarmon, [56] References Cited New South Wales, Australia UNITED STATES PATENTS Assigneel spurways Indusfiies Limited, 3,164,283 1/1965 Olson .29 24352 Alexandria, New South Wales, AUS- 3,457,763 7/1969 Freeman ..72/39l tralia Primary Examiner-Robert C. Riordon [22] Filed Dec. 1970 Assistant Examiner.l. C. Peters [21 App]. No.: 94,796 Att0rneyStevens, Davis, Miller 8L Mosher [30] Foreign Application Priority Data [57] ABSTRACT An improved fluid operated rivet pulling tool for Dec. 23, 1969 Austraha 6568O forming a head on the far Side of the work. The tool is adaptable to use on a variety of rivet sizes with minor [52] US. Cl ..72/391, 294243.52 addition or interchange of parts Such as an additional [5 1] lift. Ci. piston and associated Cylinder block ports. I [58] Field of Search..29/243.52, 243.53, 252, 200 D,

1 Claim, 4 Drawing Figures PATENIEUFEB 6 1913 3,714.81 0 SHEET 1 OF 3 PAIENIEDFEB 6|973 I 3,714,810 SHEET 20F 3 BLIND RIVET PULLING TOOL This invention relates to pneumatically operated tools for heading blind rivets; that is, tools whereby a blind rivet is applied to the work from one side thereof (the near-side) and, working from the near-side, a head is formed on the rivet on the'far-side of the work.

Such blind rivets comprise a tubular shank having a head on one end; when they are to be applied to the work the stem of a mandrel (consistingof a stern and a head) is inserted in the bore of the rivet so that the mandrel head is disposed at the unheaded end of the rivet, the mandrel stern then projects from the headed end of the rivet. The rivet with its mandrel so inserted is then applied to the tool, being held therein by a chuck forming part of the tool taking hold of the projecting end portion of the mandrel stem; with the rivet so held the rivet shank is inserted in the rivet hole in the work and while the headed end of the rivet is held hard against the near-side of the work the tool pulls on the mandrel so that its head de-forms the far-side end of the rivet thus to give it a far-side head and at the same time clinch it tightly relative to the work.

Continued pulling on the mandrel stem causes it to break, so that its headed end remains with the work (or falls from the work on the far-side thereof) and the broken end portion of the stem remains with the tool and may be discarded in any convenient manner. To ensure that the mandrel stems will always fracture in the same manner they are preferably provided with a circumferential weakening groove.

Rivet pulling tools of the kind in question are already well known, they are operated by use of compressed air as working fluid and they have proved entirely suited to the work. A major disability however is that different sized rivets and mandrels therefore call for different degrees of pulling load to be applied to the mandrel stems to ensure them clinching in the work effectively. Because of this the pulling tools used heretofore have been made in a number a different sizes corresponding to the number of different sized rivets employed. This means for example, that if a user wishes to employ three different sizes of rivets then he is faced with having to purchase three entire pulling tools.

The object of this invention is to overcome the indicated disability in a very simple way by the provision of a blind rivet pulling tool which can be made as a minimum capacity tool, and with minor addition or additions thereto maybe readily modified to suit any required higher capacity, thus irrespective of the required size of the tool, most of its parts may be used in common with various differently sized adaptations of the tool.

The invention consists in a blind rivet pulling tool comprising a hand-piece, a cylinder block mounted on said hand-piece, a front cover for said cylinder block, a mounting tube which extends concentrically and forwardly of said cover, a tubular dolly button in the forward end of said tube into which the stem ofa mandrel associated with a tubular rivet may be inserted, chucking means inside said mounting tube able to take hold of the near end of a mandrel stem inserted in said dolly button, a piston rod whereon said chucking means are mounted and which extends into said cylinder block, a piston fixed on said piston rod for working movement within said cylinder block, and

manually controllable valve and port means associated 'a working fluid under pressure may be admitted to said cylinder block for operation of said piston.

Examples of the invention are illustrated in the drawings herewith.

FIG. 1 is a medial section side elevation of a rivet pulling tool of minimum capacity;

FIGS. 2 and 3 are similar views of two higher capacity tools respectively; I

FIG. 4 shows the hand-piece porting arrangements for a hand-piece of the kind shown in FIGS. 2 and 3.

Referring to FIG. 1 the hand-piece 4 has the cylinder block 5 mounted on it by way of set screws or the like (not shown). The hand-piece and the block each have flat mating surfaces 6 and 7 which constitute suitable porting faces (see FIG. 4). The cylinder block of FIG. 1 comprises a single chamber 8 which is closed at its forward end by cover 9. Cover 9 and block 5 are bolted together as indicated at 10. Cover 9 carries a mounting tube consisting of forward portion 11 which screws within rearward portion 12. The forward end of this mounting tube carries the tubular dolly button indicated at 13. This button has a bore 14 which is able neatly to receive the mandrel stem of a tubular rivet.

A conventional chucking device is included within the forward end of the mounting tube; it consists of a frusto-conical array of jaws 15 which are squeezed together to take hold of a rivet mandrel stem by rearward movement of conical sleeve 16 assisted by thrust block 17 thrust forwardly by spring 18; the sleeve 16 is fixed on the forward end of piston rod 19 which carries piston 20 furnished with cushioning washer 21.

When the mandrel stem has been inserted within the button 13 so that it extends within grip ambit of the chuck jaws 15, the operator simply presses button 22 and this action, through conventional control valve structure 23, causes compressed air to pass from inlet 24 to the forward side of piston 20 by way of port 25. This causes the piston to move rearwardly and this in turn causes the chuck to seize the inserted mandrel stem in the performance of a riveting operation. During this rearward working stroke the cylinder port 26 is I open to atmosphere by way of the valve mechanism 23 and exhaust passage 27.

When the riveting operation is complete the operator releases button 22 and the air pressure from inlet 24 suffices to revert the button 22 and the valve mechanism associated therewith to the of position shown in FIG. 1; this opens port 25 to exhaust and port 26 to air pressure so that the piston 20 is returned to the non-working position shown in FIG. 1 and the chuck releases its hold on the portion of mandrel stem remaining in it. This portion is then free to pass along tube 28 where it may simply fall from the machine or be collected in a bag or the like indicated at 29.

When a larger capacity pulling tool is required the arrangement shown in FIG. 2 may be employed. The parts of this embodiment which are common to it and the arrangement shown in FIG. 1 will be apparent from the drawings.

Referring to FIG. 2 it will be seen that handle 4a is identical to handle 4 except for having been provided with a rearward extension 30. The cylinder block now consists of two chambers 8 and 8a; chamber 8 being the same as that marked by the same number in FIG. 1 and chamber 8a also being exactly the same except for its rearmost bead 31 having been machined to provide a step into which the forward end of chamber 8 is inserted. The porting arrangement is such that both of the cylinders 8 and 8a operate as though they were a single cylinder in the same way as described with referenceto FIG. 1. That is to say, when button 22 is depressed compressed air proceeds to ports 25 and 25a while ports 26 and 26a are open to atmosphere. Similarly, during the return stroke compressed air is admitted to the cylinder by way of ports 26 and 260 while ports 25 and 25a are open to atmosphere.

Another difference between FIG. 1 and FIG. 2 is that in providing two pistons and 20a the piston rod 19a is necessarily extended.

It is believed that the form of the invention illustrated in FIG. 3 will be virtually self-explanatory in that it merely adds a further cylinder chamber 8b to those previously referred to and numbered 8a and 8. In this form of the invention however the port 26 may be permanently open to atmosphere thus permitting the handpiece 4b to be virtually the same as that shown in FIG. 2. The reason for this is that the return stroke of the piston assembly needs far less power than the working stroke in which'the mandrel stem is tensioned to the point of breakage. Thus in the FIG. 3 arrangement all three pistons are effective for rivet pulling purposes whereas pistons 8a and 8b alone are sufficiently powerful for executing the return stroke of the piston rod.

I claim:

1. A blind rivet pulling tool comprising a hand-piece,

said tube into which the stern of a mandrel associated with a tubular rivet may be inserted, chucking means inside said mounting tube able to take hold of the near end of a mandrel stem inserted in said dolly button, a first piston rod whereon said chucking means are mounted and which extends into said first cylinder block, a first piston fixed on said first piston rod for working movement within said first cylinder block, at least one additional cylinder block co-axially secured to the first cylinder block,'an additional piston in said additional cylinder block, an extension of said first piston rod for mounting said additional piston, and port means in said additional cylinder block whereby the additional piston is operable concertedly with the first piston, and manually controllable valve and port means associated with said hand-piece and said cylinder blocks, whereby a working fluid under pressure may be admitted to said cylinder blocks for operation of said pistons. 

1. A blind rivet pulling tool comprising a hand-piece, a first cylinder block mounted on said hand-piece, a front cover for said first cylinder block, a mounting tube which extends concentrically and forwardly of said cover, a tubular dolly button in the forward end of said tube into which the stem of a mandrel associated with a tubular rivet may be inserted, chucking means inside said mounting tube able to take hold of the near end of a mandrel stem inserted in said dolly button, a first piston rod whereon said chucking means are mounted and which extends into said first cylinder block, a first piston fixed on said first piston rod for working movement within said first cylinder block, at least one additional cylinder block co-axially secured to the first cylinder block, an additional piston in said additional cylinder block, an extension of said first piston rod for mounting said additional piston, and port means in said additional cylinder block whereby the additional piston is operable concertedly with the first piston, and manually controllable valve and port means associated with said hand-piece and said cylinder blocks, whereby a working fluid under pressure may be admitted to said cylinder blocks for operation of said pistons. 